Jessica Chastain, tipped for an Oscar for her role in Osama bin Laden manhunt movie Zero Dark Thirty, says it should serve as a tribute to the CIA agent who was key to finding the Al-Qaeda chief.
The movie by Academy Award-winning director Kathryn Bigelow tells the story of the
decade-long search after September 11, 2001, climaxing in last year's dramatic and deadly raid on Bin Laden's hideout in Abbottabad, Pakistan.

The CIA agent known as Maya, played with fierce intensity by Chastain, is seen driving her bosses relentlessly to focus on leads which eventually identify a courier who totes messages to and from the Abbottabad compound.

"I've never had really a responsibility like this. I'm playing a real woman, and that's a huge responsibility because I really admire Maya and I don't want to feel I betrayed her," said the US actress, using her character's pseudonym.

"She can't take credit for what she accomplished because she's undercover. She can't call out the press and say 'It was me.' So making this movie is like thanking her and giving her credit for what she's done," she told AFP.

"I had a huge responsibility for not messing that up," added the actress, who could not meet the CIA agent to help her prepare for the role, because she remains on active duty for the US spy agency.

Bigelow, whose 2008 The Hurt Locker won six Oscars, had already begun work on the Bin Laden film -- with the same screenwriter, Mark Boal -- when US commandos stormed the Al-Qaeda leader's compound and killed him on May 1, 2011.

The project had focused mainly on the decade-long hunt, and the agent at the center of it, but the movie was transformed by events into the tale of one of the biggest US military successes since 9/11.

Controversy surrounded it even before its release: claims that the filmmakers were given access to classified information fueled criticism that it would serve as propaganda for President Barack Obama's re-election bid.

The film -- named after military-speak for the time of the nocturnal Abbottabad raid -- also pulls no punches in showing the use of torture and harsh interrogation techniques like water-boarding to force captives to speak.

Information obtained by such methods is shown as crucial in piecing together the trail which eventually leads to Bin Laden -- and CIA officers are clearly disappointed when the newly-elected Obama declares an end to torture in 2009.

But the film itself -- which won best film and best director from the New York Film Critics Circle and has four Golden Globes nominations -- avoids almost all politicizing to focus unflinchingly on the hunt for bin Laden.

Even Maya's private life is virtually absent, with not even a hint of romance to lighten the tone -- an element which Chastain says is true to reality.

"That's exactly how she was. She didn't have a boyfriend. She didn't have a personal life. For her, the most important thing was her job and finding this man," said the actress.

Chastain says Maya was -- and is -- a strong female character.

"A lot of female lead characters, in films, are defined by the man in their life, are defined by their children, or are defined by being a victim," said Chastain.

"But this woman is capable and intelligent. She's the perfect representation of the current generation of women. And for me, it was actually very exciting to approach a character like that."

The movie climaxes inevitably with the Abbottabad raid and bin Laden's death, a massively cathartic moment for America that triggered celebrations across the country and further afield.

But even here the emotion is restrained in Bigelow's movie, with a single "whoop" from one of the returning Seals as they unload his bodybag from the helicopter.

The final scene is of Maya, climbing aboard a military transport plane as the only passenger and being asked where she wants to go, having just accomplished what she had been striving for ever since 9/11.

"When, at the very end, she's asked 'Where do you wanna go?' she really has nowhere to go. Who is she? And the question is not only 'Who is she?' but also 'Who are we, as a country and as a society of people?'

"And I think it's really brave for Kathryn and Mark. It's not just 'Hurray, we killed Bin Laden.' That's not what the movie is about. In the end, it's: 'Where do we go now?'"